Seedlings of three different Scots pine (Pinus sylvestris L.) nursery stock, 1+0 ,1+1, and 2+0, were kept over the winter, after they had been packed in polythene bags, in three different ways: 1) In a refrigerated storage room, 2) in a wooden crate in the ground, 3) submerged in a lake. The seedling to which they were to be compared with were left over the winter in a nursery bed. The 1,800 seedlings were planted out in the spring 1966 in 15 random blocks. Their development was scrutinized during the three subsequent falls.

The seedlings which had been stored in the lake all died. The seedlings which had been stored along the 1st and 2nd method, managed almost as well as the ones which had been kept over the winter in the nursery bed, except for those of 1+0 stock.

The aim of the study was to investigate the effect of four packing methods on the field survival and growth of seedlings and transplants of Scots pine (Pinus sylvestris L.) stored over the winter in a cold-storage cellar. The following sorts of plants were used: one-year-old seedlings (1+0) grown in a plastic greenhouse, two-year-old (2+0) open grown seedlings and three-year-old open grown transplants. These plants were stored in open wooden boxes, in sealed plastic bags, in boxes with wet peat on the bottom and in plastic-laminated paper bags.

The control plants were of the same types and were kept in a nursery over the winter. The storage was carried out in a mantle-chilled cold-storage from October 1966 to May 1967. The temperature in the cold-storage was kept around -2 °C and the relative humidity of the air over 90%. The water content of a randomly selected sample plants showed no increase in water deficit after the storing. Part of the seedlings were transplanted in the nursery and the rest were planted in a clear-cut area. A number of the latter plants were treated with an insecticide (1% Intaktol, which contains DDT, Lindane and dieldrin) before planting. All the experiments were examined after one growing season and the planting experiments the next fall.

The transplants (2+1) in the nursery, and in the forest had survived and grown better than the seedlings. In the nursery the 1+0 seedlings survived and grew better than the 2+0 seedlings. There was no difference in mortality between the seedlings. After the first growing season occasional significant differences between the packing methods were observed, but they disappeared during the second growing season. Thus, all packing methods proved to be as successful as the control method without winter storage.

Transplants were more often attacked by the large pine weevil (Hylobius abietis L.) than the smaller seedlings. The damage, however, was considerably greater on the seedlings because of their lower resistance. No significant differences in the Hylobius-attack between the packing methods could be observed. The Intaktol-treated plants were as often attacked as the untreated ones, but the damage was slighter on the treated ones.

The aim of the study was to establish how the cold storage of cones of Norway spruce (Picea abies (L.) H. Karst.) affects the viability of the seeds and the percentage ratio in 7 days. A parallel study was made of the longevity of seed in barn-stored cones subject to weather fluctuations and the longevity of seed extracted immediately and stored in the conventional way in an air-tight container. The cones were collected near Kuopio in Central Finland and near Tampere.

The viability and germination rate of the control sample was constant throughout the storage period. This storage method proved the best. The viability of seeds kept in cones declined in cold storage after 3 ½ months. The cones collected in Tampere were damaged by Laspeyresia strobilella, which affected the viability of the seeds.

The viability of seeds stored in cones in a barn had not weakened by the end of May, however, they deteriorated during the summer, as did the seeds stored in cones in the cold storage. Viability of the seeds was still 94% in October. The germination rate was constant in each lot up to the end of May, after which it decreased to 81.7–86.1% in October.

The results show that healthy spruce cones can be stored in paper sacks in a single layer in cold storage and in an ordinary barn for several months without it affecting the viability of the seeds.

The aim of this study was to find out the planting vigour of Scots pine (Pinus sylvestris L.) stored over the winter either in winter storage mainly in the temperature of 4 – -6 °C or in nursery beds. The experimental planting included about 4,500 of 2+1 transplants in Northern Finland. In spring 1965 the control plants were lifted in the spring before budbreak and stored in closed bags in a cold store, in the following year the control plants were lifted in June when the growth had started.

Winter storage of pine transplants in a cold store, tightly closed into bags for the major period, did not, according to the results, increase plant mortality as compared to lifting in the spring. Soaking the stored-plant roots did not affect plant mortality. Mortality was rather small in all treated lots and probably more dependent on planting site and other local factors.

No consistent difference on the leader growth, needle length, bud number and plant grade was found between the plants stored over winter and those lifted in the spring. Sealing the plants into tight bags for winter proved to be suitable method, efficiently preventing water shortage in the plants. No moulds or fungal diseases were found in the plants. In the exceptionally cold 1965–1966 winter, temperature in the cold store sank to -15 °C, but in spite of the temperatures below the recommended storing temperature, the plants survived well. The reason was that the plants froze slowly in the fall and thawed out slowly in the spring.

The value of vigour grade in predicting plant-characteristic development proved to be good, and predicted plant development also in the following year fairly well.